Outboard motor, control apparatus and control method for outboard motor

ABSTRACT

A control apparatus for an outboard motor (4, 5) mounted on a hull (2), comprises a detection unit (46) that detects a variation of rotation of a propeller (25), a protruding portion (60) provided at a rear end portion (25b) of the propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2), and a control unit (30, 40) that determines that an object has contacted the protruding portion (60) when a variation of rotation of the propeller (25) exceeds a predetermined threshold is detected.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of Japanese Patent Application No. 2021-215078 filed on Dec. 28, 2021, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an outboard motor, a control apparatus and a control method for the outboard motor.

Description of the Related Art

Japanese Patent Laid-Open No. 2021-70456 describes a configuration including a cylindrical protective cover covering a propeller to prevent objects from wrapping around the propeller.

Japanese Patent Laid-Open No. 2021-70456 does not describe a configuration in which a protruding portion that rotates integrally with a propeller is attached to the propeller to determine that an object has contacted the propeller by the variation of rotation of the propeller.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the above described backgrounds and realizes techniques to attach a protruding portion that rotates integrally with a propeller to avoid contact of an object with the propeller.

The present invention also realizes techniques to determine that an object has contacted the propeller by the variation of rotation of the propeller by attaching the protruding portion that rotates integrally with the propeller.

In order to solve the above described backgrounds, according to the 1st aspect of the present invention, there is provided an outboard motor (4, 5) mounted on a hull (2) comprising: a protruding portion (60) provided at a rear end portion (25 b) of a propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2).

According to the 2nd aspect of the present invention, in the 1st aspect, the protruding portion (60) is arranged coaxially with a rotary axis (R3) of the propeller (25).

According to the 3rd aspect of the present invention, in the 1st or 2nd aspect, the protruding portion (60) extends from the propeller (25) to the rear of the hull (2).

According to the 4th aspect of the present invention, in any one of the 1st to 3rd aspect, the protruding portion (60) includes an elastic material.

According to the 5th aspect of the present invention, in any one of the 1st to 4th aspect, the protruding portion (60) is equipped with an airbag (61).

According to the 6th aspect of the present invention, in any one of the 1st to 5th aspect, the protruding portion (60) is detachably attached to the propeller (25).

According to the 7th aspect of the present invention, in any one of the 1st to 6th aspect, the outboard motor includes a first outboard motor (4) and a second outboard motor (5), which are spaced apart in a width direction of the hull (2).

According to the 8th aspect of the present invention, there is provided a control apparatus for an outboard motor (4, 5) mounted on a hull (2), comprising: a detection unit (46) that detects a variation of rotation of a propeller (25); a protruding portion (60) provided at a rear end portion (25 b) of the propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2); and a control unit (30, 40) that determines that an object has contacted the protruding portion (60) when a variation of rotation of the propeller (25) exceeds a predetermined threshold is detected.

According to the 9th aspect of the present invention, in the 8th aspect, the protruding portion (60) is arranged coaxially with a rotary axis (R3) of the propeller (25).

According to the 10th aspect of the present invention, in the 8th or 9th aspect, the protruding portion (60) extends from the propeller (25) to a rear of the hull (2).

According to the 11th aspect of the present invention, in any one of the 8th to 10th aspect, the protruding portion (60) includes an elastic material.

According to the 12th aspect of the present invention, in any one of the 8th to 11th aspect, the control unit (30, 40) issues a warning when the control unit (30, 40) determines that an object has contacted the protruding portion (60).

According to the 13th aspect of the present invention, in any one of the 8th to 11th aspect, the control unit (30, 40) stops the propeller (25) when the control unit (30, 40) determines that an object has contacted the protruding portion (60).

According to the 14th aspect of the present invention, in any one of the 8th to 11th aspect, the protruding portion (60) is equipped with an airbag (61), and the control unit (30, 40) deploys the airbag (61) when the control unit (30, 40) determines that an object has contacted the protruding portion (60).

According to the 15th aspect of the present invention, in any one of the 8th to 14th aspect, the predetermined threshold is different when the object is a person and when the object is not a person.

According to the 16th aspect of the present invention, in any one of the 8th to 15th aspect, the variation of rotation is a variation of angular velocity or angular acceleration of a drive shaft (25 a) of the propeller (25).

According to the 17th aspect of the present invention, in any one of the 8th to 16th aspect, the protruding portion (60) is detachably attached to the propeller (25).

According to the 18th aspect of the present invention, in any one of the 8th to 17th aspect, the outboard motor includes a first outboard motor (4) and a second outboard motor (5), which are spaced apart in a width direction of the hull (2).

According to the 19th aspect of the present invention, there is provided a method of controlling an outboard motor (4, 5) mounted on a hull (2), wherein the outboard motor (4, 5) has a protruding portion (60) provided at a rear end portion (25 b) of a propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2), the method comprising: detecting a variation of rotation of the propeller (25); and determining that an object has contacted the protruding portion (60) when a variation of rotation of the propeller (25) exceeds a predetermined threshold value is detected.

According to the present invention, a protruding portion that rotates integrally with a propeller is attached to the propeller, thereby avoiding the propeller from contacting an object.

In addition, a protruding portion that rotates integrally with a propeller is attached to the propeller, allowing determination of object contact by the variation of rotation of the propeller.

Specifically, according to first, second, and nineteenth aspects of the present invention, a protruding portion 60 is provided at a rear end portion 25 b of a propeller 25 and extends from the propeller 25 to the rear of a hull 2, so that even if an object approaches an outboard motor 4, 5, it will contact the protruding portion 60 before it touches the propeller 25, thus avoiding contact of the object with the propeller 25.

According to a third aspect of the present invention, the protruding portion 60 is arranged coaxially with the rotary axis R3 of the propeller 25, so it does not affect the traveling performance of the hull.

According to fourth aspect of the present invention, the protruding portion 60 is made of an elastic material, which can mitigate the impact of an object contacting the protruding portion 60.

According to a fifth aspect of the present invention, the protruding portion 60 is equipped with an airbag 61, so that the airbag 61 can push the object that has contacted the protruding portion 60 away from the propeller 25. When the object in contact with the protruding portion 60 is a human, the human body can be protected from the propeller 25 by deploying the airbag 61.

According to a sixth aspect of the present invention, the protruding portion 60 can be removed depending on the application, which improves convenience.

According to a seventh aspect of the present invention, each of the outboard motors 4 and 5 includes the protruding portion 60, so that contact of an object with the propeller 25 can be avoided in each outboard motor.

According to eighth and ninth aspects of the present invention, the protruding portion 60 is provided at the rear end portion 25 b of the propeller 25 and extends from the propeller 25 to the rear of a hull 2, so that even if an object approaches an outboard motor 4, 5, it will contact the protruding portion 60 before it touches the propeller 25, so that object contact can be determined while avoiding object contact with the propeller 25. It can also determine that an object approaching from behind the hull 2 has made contact, which may assist the operator in visually confirming contact with the object.

According to a tenth aspect of the present invention, the protruding portion 60 is arranged coaxially with the rotary axis R3 of the propeller 25, allowing determination that an object has contacted with the protruding portion 60 without affecting the traveling performance of the hull.

According to an eleventh aspect of the present invention, the protruding portion 60 is made of an elastic material, which mitigates the impact of an object contacting the protruding portion 60 while reliably generating variation of rotation in the propeller 25, thereby enabling determination that an object has contacted the protruding portion 60.

According to a twelfth aspect of the present invention, an outboard motor controller 40 issues a warning when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, thereby notifying the operator that an object has contacted the protruding portion 60 and alerting the operator. When the object is a person, a warning can be issued to avoid danger.

According to a thirteenth aspect of the present invention, the outboard motor controller 40 stops the propeller 25 when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, so that when an object contacts the protruding portion 60, the propeller can be stopped urgently without waiting for the crew to take action.

According to a fourteenth aspect of the present invention, the protruding portion 60 includes an airbag 61, and the outboard motor controller 40 deploys the airbag when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, so that the airbag 61 can push the object that has contacted the protruding portion 60 away from the propeller 25. When the object in contact with the protruding portion 60 is a human, the human body can be protected from the propeller 25 by deploying the airbag 61.

According to a fifteenth form of the present invention, contact determination can be performed with priority given to a person as a protected obj ect.

According to a sixteenth aspect of the present invention, the amount of variation in angular velocity or angular acceleration can be calculated from the direction of rotation and rotational speed of a drive shaft 25 a of the propeller 25, making detection simple and inexpensive.

According to a seventeenth aspect of the present invention, the protruding portion 60 can be removed depending on the application, which improves convenience.

According to an eighteenth aspect of the present invention, each of the outboard motors 4 and 5 includes the protruding portion 60, so that object contact with the propeller 25 can be determined in each outboard motor.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the exterior configuration of a vessel according to the present embodiment;

FIG. 2 is a side view of an outboard motor according to the present embodiment;

FIG. 3 is a block diagram illustrating the control configuration of a vessel according to the present embodiment;

FIG. 4 is a block diagram illustrating the control configuration of an outboard motor according to the present embodiment;

FIG. 5 is a diagram illustrating the control configuration for performing a contact determination according to the present embodiment.

FIG. 6 is a flowchart illustrating a contact control according to the present embodiment.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments are not intended to limit the scope of the claimed invention, and limitation is not made an invention that requires all combinations of features described in the embodiments. Two or more of the multiple features described in the embodiments may be combined as appropriate. Furthermore, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.

External Appearance and Configuration of Vessel 1

FIG. 1 is a perspective view of the external appearance configuration of the vessel to which the control apparatus for the outboard motors of the present embodiment are applied.

As illustrated in FIG. 1 , the vessel 1 includes a plurality of (for example, two) outboard motors (a first outboard motor 4 and a second outboard motor 5). The first outboard motor 4 and the second outboard motor 5 are mounted on a stem 3 of a hull 2. The first outboard motor 4 and the second outboard motor 5 are spaced apart by a predetermined distance in the width direction of the stern 3. The first outboard motor 4 is disposed on the port side of the stem 3. The second outboard motor 5 is disposed on the starboard side of the stem 3. The first outboard motor 4 and the second outboard motor 5 generate a propulsion to propel the hull 2.

A steering apparatus 6, a remote controller 7, and instruments 9 are provided near the steering seat of the hull 2. The steering apparatus 6 includes a steering wheel that allows the operator to control the turning direction of the hull 2. The remote controller 7 includes a shift lever 8 that allows the operator to adjust the speed of the hull 2 and switch between forward and backward movement of the hull 2. The instruments 9 include indicators that display the position, speed, and others of the vessel 1, and alarms that report abnormalities.

External Appearance and Configuration of Outboard Motor 4, 5

FIG. 2 is a side view of the first outboard motor 4 and the second outboard motor 5. The configuration of the first outboard motor 4 and the second outboard motor 5 are identical.

The first outboard motor 4 and the second outboard motor 5 include an outboard motor body 21 and a bracket 22. The outboard motor body 21 includes a cover member 23, a prime mover 24, a propeller 25, a steering actuator, and a trim actuator 27. The cover member 23 houses the prime mover 24. The prime mover 24 and the propeller 25 are connected by a power transmission mechanism (not illustrated), and the propeller 25 is rotated and driven by the driving force of the prime mover 24. The prime mover 24 is an engine or electric motor that drives the propeller 25.

The bracket 22 is a mounting mechanism for detachably attaching the first outboard motor 4 and the second outboard motor 5 to the stem 3. The first outboard motor 4 and the second outboard motor 5 are rotatably attached around a trim axis R1 of the bracket 22 by the trim actuator 27. By rotating the first outboard motor 4 and the second outboard motor 5 around the trim axis R1, the trim angle, which is the tilt of the first outboard motor 4 and the second outboard motor 5 in the pitching direction (trim direction) with respect to the hull 2, can be changed. The first outboard motor 4 and the second outboard motor 5 are attached by the steering actuator 26 to be rotatable around the steering axis R2 of the bracket 22. By rotating the first outboard motor 4 and the second outboard motor 5 around the steering axis R2, the steering (rudder) angle, which is the yaw direction (steering direction) tilt of the first outboard motor 4 and the second outboard motor 5 with respect to the hull 2, can be changed. Thus, by changing the trim angle and steering angle of the first outboard motor 4 and the second outboard motor 5, the attitude in the pitching direction and turning in the yaw direction of the hull 2 are controlled. The propeller 25 can rotate around the rotary axis R3 by the driving force transmitted from the prime mover 24 to the drive shaft 25 a.

In addition, the propeller 25 includes an object contact portion 60. The object contact portion 60 is detachably attached to the rear end portion 25 b of the drive shaft 25 a of the propeller 25. The object contact portion 60 is provided coaxially with the rotary axis R3 of the propeller 25, has a streamlined shape protruding rearward from the rear end portion 25 b of the drive shaft 25 a of the propeller 25, and is conical in shape with a reduced diameter toward the rearward position of the hull 2. The object contact portion 60 rotates integrally with the drive shaft 25 a of the propeller 25. The length at which the object contact portion 60 protrudes is determined according to the size of the propeller 25, but is longer than the rear of the outboard motor body 21, so that even if an object approaches the outboard motor, it will contact the object contact portion 60 before contacting the propeller 25. The object contact portion 60 houses the airbag 61 that deploys when an object contacts it.

The object contact portion 60, for example, is made of an elastic material such as rubber that is hard enough not to deform when the propeller 25 rotates or is contacted by an object and that ensures safety during object contact, and generates a variation of rotation of the drive shaft 25 a of the propeller 25 when an object contacts it. For example, the object contact portion 60 is composed of a hard material on the inside and a soft material, such as rubber, on the outside surface.

Thus, even if an object approaches the outboard motor, it will contact the object contact portion 60 before it touches the propeller 25, so that object contact can be determined while avoiding object contact with the propeller 25.

Since the object contact portion 60 is provided at the rear end portion 25 b of the drive shaft 25 a of the propeller 25, it does not affect the traveling performance and others.

Control Configuration of Vessel 1

FIG. 3 is a block diagram illustrating the control configuration of a vessel according to the present embodiment;

In the vessel 1 of the present embodiment, a main controller 30 controls the hull 2, the first outboard motor 4, the second outboard motor 5, and the instruments 9 based on the steering operation information of the steering apparatus 6 and the operation information of the shift lever 8 of the remote controller 7. The main controller 30 includes a main electronic control unit (ECU) 31 and a storing unit 32. The main ECU 31 includes a CPU and other components that control the hull 2, the first outboard motor 4, and the second outboard motor 5 by executing a control program stored in the storing unit 32. The storing unit 32 includes a memory that stores control programs and data tables executed by the main ECU 31.

The main ECU 31 can control the first outboard motor 4 and the second outboard motor 5 independently.

Control Configuration of First Outboard Motor 4 and Second Outboard Motor 5

FIG. 4 is a block diagram illustrating the control configuration of the first outboard motor 4 and the second outboard motor 5 according to the present embodiment. The control configuration of the first outboard motor 4 and the second outboard motor 5 are identical.

In the first outboard motor 4 and the second outboard motor 5 of the present embodiment, the outboard motor controller 40 controls the prime mover 24, the steering actuator 26, the trim actuator 27, and the airbag 61 based on control information from the main controller 30. The outboard motor controller 40 includes an outboard motor electronic control unit (ECU) 41 and a storing unit 42. The outboard motor ECU 41 includes a CPU and other components that control the prime mover 24, the steering actuator 26, and the trim actuator 27 by executing a control program stored in the storing unit 42. The storing unit 42 includes a memory that stores control programs and data tables executed by the outboard motor ECU 41. The control program executed by the outboard motor ECU 41 includes a contact control program 43 described below. The data table referenced by the outboard motor ECU 41 executing the control program include the contact control table 44 referenced in the contact control program 43 described below.

The prime mover 24 is an electric motor. The driver 45 adjusts the power supplied to the electric motor. The rotation detection unit 46 includes an encoder that detects the direction and speed of rotation of the drive shaft of the prime mover 24 or the drive shaft 25 a of the propeller 25. The outboard motor ECU 41 calculates the amount of variation in the angular velocity or angular acceleration of the drive shaft 25 a of the propeller 25 based on the detection results of the rotation detection unit 46. Thus, the amount of variation in angular velocity or angular acceleration can be calculated from the direction and speed of rotation of the drive shaft 25 a of the propeller 25, making detection simple and inexpensive.

The steering actuator 26 is a stepper motor that rotates the bracket 22 around the steering axis R2. The driver 47 is a circuit that drives the steering actuator 26 to rotate around the steering axis R2.

The trim actuator 27 is a stepper motor that rotates the bracket 22 around the trim axis R1. The driver 48 is a circuit that drives and rotates the trim actuator 27 around the trim axis R1.

A power supply 50 is a battery that supplies power to the components of the first outboard motor 4 and the second outboard motor 5.

The airbag 61 is housed inside the object contact portion 60 connected to the propeller 25. The airbag 61 is controlled to deploy by the outboard motor ECU 41 at the time of contact determination as described below.

Contact Determination

Next, the contact determination and contact control of the present embodiment will be described with reference to FIGS. 5 and 6 .

The contact control of the present embodiment is used when it is determined that an object has contacted the object contact portion 60 of the first outboard motor 4 and/or the second outboard motor 5.

The contact determination of the present embodiment is realized by a contact control program 43 and a contact control table 44 executed by the outboard motor ECU 41, the rotation detection unit 46, and a contact determination unit 51.

The contact determination unit 51 is a functional block of the outboard motor ECU 41. The outboard motor ECU 41 calculates the amount of variation in the angular velocity or angular acceleration of the drive shaft 25 a of the propeller 25 based on the detection results of the rotation detection unit 46.

The outboard motor ECU 41 compares the amount of variation of the angular velocity or angular acceleration of the drive shaft 25 a of the propeller 25 with the threshold value of the amount of variation under normal conditions, and determines that some object has contacted the object contact portion 60 when the amount of variation of the angular velocity or angular acceleration of the drive shaft 25 a of the propeller 25 exceeds the threshold value. The threshold may be set differently when the object is a person and or not a person. Specifically, the threshold is set so that contact determination is easier when the object is a person than when the object is not a person. This allows contact determination to be made with priority on the person as the object to be protected. The type of the object can be determined by using techniques such as infrared (temperature) sensors or subject authentication using a camera.

At the time of contact determination, the outboard motor ECU 41 cooperates with the main ECU 31 to issue a warning via the instruments 9, emergency stop the first outboard motor 4 and/or the second outboard motor 5, or deploy the airbag 61, as necessary.

The airbag 61 pushes the object in contact with the object contact portion 60 away from the propeller 25. When the object in contact with the object contact portion 60 is a human, the human body can be protected from the propeller 25 by deploying the airbag 61.

For example, by providing an emergency button in an outboard motor at a location that can be operated by a swimmer, the airbag 61 can be forcibly triggered by a swimmer who feels that he or she is in danger.

In the contact control table 44, information such as control information for the outboard motor ECU 41 to refer to at the time of contact determination and threshold values for the amount of variation of the angular velocity or angular acceleration of the drive shaft 25 a of the propeller 25 to be referred to at the time of contact determination, are registered. The contact control table 44 is generated in advance through contact experiments.

Control Flow

FIG. 6 is a flowchart illustrating the contact control of the present embodiment.

In FIG. 6 , in step S1, the outboard motor ECU 41 obtains information from the rotation detection unit 46.

In step S2, the outboard motor ECU 41 performs contact determination based on the information obtained in step S1. The outboard motor ECU 41 performs contact determination based on the information obtained in step S1 and the thresholds obtained from the contact control table 44. When the outboard motor ECU 41 determines that a contact has occurred, the processing proceeds to step S3 to perform contact control, and when the outboard motor ECU 41 determines that no contact has occurred, the processing proceeds to step S4 to perform normal control.

In step S3, the outboard motor ECU 41 performs contact control, which urgently stops the first outboard motor 4 and the second outboard motor 5 or activates the airbags 61 in accordance with the contact control program 43.

In step S4, the outboard motor ECU 41 controls the system according to a normal control program 33.

According to the present embodiment, the protruding object contact portion 60 that rotates integrally with the propeller 25 is attached to the propeller 25, allowing objects to avoid contacting the propeller 25. It is also possible to determine object contact by the variation of rotation of the propeller 25.

The protruding portion 60 is provided at the rear end portion 25 b of the propeller 25 and extends from the propeller 25 to the rear of the hull 2, so that even if an object approaches the outboard motor 4, 5, it will contact the protruding portion 60 before it touches the propeller 25, so that object contact can be determined while avoiding object contact with the propeller 25. It can also determine that an object approaching from behind the hull 2 has made contact, which may assist the operator in visually confirming contact with the object.

The protruding portion 60 is arranged coaxially with the rotary axis R3 of the propeller 25, allowing determination that an object has contacted the protruding portion 60 without affecting the traveling performance of the hull.

The protruding portion 60 is made of an elastic material, which mitigates the impact of an object contacting the protruding portion 60 while reliably generating a variation of rotation of the propeller 25, allowing determination that an object has contacted the protruding portion 60.

The outboard motor controller 40 issues a warning when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, thereby notifying the operator that an object has contacted the protruding portion 60 and alerting the operator. When the object is a person, a warning can be issued to avoid danger.

The outboard motor controller 40 stops the propeller 25 when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, so that when an object contacts the protruding portion 60, the propeller can be stopped urgently without waiting for the crew to take action.

The protruding portion 60 is equipped with the airbag 61, and the outboard motor controller 40 deploys the airbag when the outboard motor controller 40 determines that an object has contacted the protruding portion 60, so that the airbag 61 can push the object that has contacted the protruding portion 60 away from the propeller 25. When the object in contact with the protruding portion 60 is a human, the human body can be protected from the propeller 25 by deploying the airbag 61.

The threshold for contact determination is set differently when the object is a person and when it is not a person, so that the contact determination can be made with priority on the person as the object to be protected.

In addition, the amount of variation in angular velocity or angular acceleration can be calculated from the direction and speed of rotation of the drive shaft 25 a of the propeller 25, making detection simple and inexpensive.

The protruding portion 60 can be removed depending on the application, which improves convenience.

Each of the outboard motors 4 and 5 includes the protruding portion 60, so that object contact with the propeller 25 can be determined in each outboard motor while avoiding object contact with the propeller 25 in each outboard motor.

The present invention is not limited to the above embodiments, and thus various modifications and changes may be made within the scope of the gist of the present invention. For example, the present embodiment includes two outboard motors, but the number of outboard motors is not limited to two and may be one or three or more.

In the present invention, a computer program corresponding to the control of outboard motors of the above described embodiment or a storage medium containing the computer program may be supplied to a computer controlling the hull 2 and the outboard motors 4, 5, so that the computer reads and executes the program code stored in the storage medium. 

What is claimed is:
 1. An outboard motor (4, 5) mounted on a hull (2) comprising: a protruding portion (60) provided at a rear end portion (25 b) of a propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2).
 2. The outboard motor according to claim 1, wherein the protruding portion (60) is arranged coaxially with a rotary axis (R3) of the propeller (25).
 3. The outboard motor according to claim 1, wherein the protruding portion (60) extends from the propeller (25) to the rear of the hull (2).
 4. The outboard motor according to claim 1, wherein the protruding portion (60) includes an elastic material.
 5. The outboard motor according to claim 1, wherein the protruding portion (60) is equipped with an airbag (61).
 6. The outboard motor according to claim 1, wherein the protruding portion (60) is detachably attached to the propeller (25).
 7. The outboard motor according to claim 1, wherein the outboard motor includes a first outboard motor (4) and a second outboard motor (5), which are spaced apart in a width direction of the hull (2).
 8. A control apparatus for an outboard motor (4, 5) mounted on a hull (2), comprising: a detection unit (46) that detects a variation of rotation of a propeller (25); a protruding portion (60) provided at a rear end portion (25 b) of the propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2); and a control unit (30, 40) that determines that an object has contacted the protruding portion (60) when a variation of rotation of the propeller (25) exceeds a predetermined threshold is detected.
 9. The apparatus according to claim 8, wherein the protruding portion (60) is arranged coaxially with a rotary axis (R3) of the propeller (25).
 10. The apparatus according to claim 8, wherein the protruding portion (60) extends from the propeller (25) to a rear of the hull (2).
 11. The apparatus according to claim 8, wherein the protruding portion (60) includes an elastic material.
 12. The apparatus according to claim 8, wherein the control unit (30, 40) issues a warning when the control unit (30, 40) determines that an object has contacted the protruding portion (60).
 13. The apparatus according to claim 8, wherein the control unit (30, 40) stops the propeller (25) when the control unit (30, 40) determines that an object has contacted the protruding portion (60).
 14. The apparatus according to claim 8, wherein the protruding portion (60) is equipped with an airbag (61), and the control unit (30, 40) deploys the airbag (61) when the control unit (30, 40) determines that an object has contacted the protruding portion (60).
 15. The apparatus according to claim 8, wherein the predetermined threshold is different when the object is a person and when the object is not a person.
 16. The apparatus according to claim 8, wherein the variation of rotation is a variation of angular velocity or angular acceleration of a drive shaft (25 a) of the propeller (25).
 17. The apparatus according to claim 8, wherein the protruding portion (60) is detachably attached to the propeller (25).
 18. The apparatus according to claim 8, wherein the outboard motor includes a first outboard motor (4) and a second outboard motor (5), which are spaced apart in a width direction of the hull (2).
 19. A method of controlling an outboard motor (4, 5) mounted on a hull (2), wherein the outboard motor (4, 5) has a protruding portion (60) provided at a rear end portion (25 b) of a propeller (25) to rotate integrally with the propeller (25) and extending from the propeller (25) to a rear of the hull (2), the method comprising: detecting a variation of rotation of the propeller (25); and determining that an object has contacted the protruding portion (60) when a variation of rotation of the propeller (25) exceeds a predetermined threshold value is detected. 